1. Field of the Invention
The invention relates in general to an impact cushion mechanism for an optical pick up head, and more particularly to an impact cushion mechanism for an optical pick up head applied in an optical disc drive.
2. Description of the Related Art
Whenever an ordinary optical disc drive is started, the pick up head will return to the stay-home position through a reciprocate process of colliding with the chassis. Moreover, if the compact disc in use has defects or is of poor quality, the pick up head might misjudge and strike the chassis inward or outward; therefore, the problems and pick up head dislocation and damages of related parts may arise.
FIG. 1 is a top view of a conventional optical disc drive, wherein an optical pick up head 102 can move back and forth along two guide bars by means of an driving mechanism 106. Conventionally, there is no any impact cushion design for the driving mechanism 106, except for a solid plastic 108 being attached to the front and the rear of the driving mechanism 106. When the pick up head 102 strikes the chassis 110 inward or outward, the solid plastic 108 will directly collide with the chassis 110, producing not any practical protection but noises. The schematic illustration in FIG. 2A and FIG. 2B shows respectively the collision status before and after the solid plastic 108 driving mechanism colliding with the chassis 110 of FIG. 1.
Besides, some of the conventional designs install a limit switch i near the inner part of the disc, for limiting the movement of the pick up head via a contact starter. However, without having any particular impact cushion mechanism installed near the outer part of the disc, the pick up head is likely to be damaged due to the striking outward collision.
As disclosed hereinbefore, how to design an impact cushion mechanism appropriately, which can reduce the impact force the pick up head receives, effectively prevent the dislocation of the pick up head, protect the pick up head and related parts from damage and further prolong the life of the optical disc drive, has become a considerable issue to R&D engineers in related fields.